This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present disclosure that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
iOS applications are protected against reverse engineering by encrypted distribution from the originator to the iOS device on which they are to be installed. Once installed on the iOS device, the iOS itself protects the applications against dynamic analysis using isolation of processes and separation of privileges.
However, the protection only applies to iOS devices that have not been jailbroken. It is easy to use a GNU debugger (gdb) to dump the code of an application from a jailbroken device, as explained by Jonathan Zdziarski in “Hacking and Securing iOS Applications”. A jailbroken device has been modified in order to obtain increased privileges that are not available on a device that has not been jailbroken.
It is thus not sufficient to rely on the protection provided by the iOS. But since the iOS does not allow any code modifications within installed applications, the only software protection mechanisms that can be used are integrity checks and Control Flow Graph (CFG) flattening, both of which are commonly used together. These software protection mechanisms are often needed since the encryption provided by the iOS is weak and the application also is vulnerable to reverse engineering using static analysis.
Then again, CFG flattening is only efficient against static attacks, not dynamic attacks, and Wurster et al. have shown that it is possible to circumvent integrity checks by running two code sections parallel, as described in “A Generic Attack on Checksumming-Based Software Tamper Resistance.”
It will be appreciated that it is desired to have a solution that overcomes at least part of the conventional problems related to protection of iOS applications. The present principles provide such a solution.